Hi-Endurance Switching, Sensing
& Linear Position Sensors

Waterproof Plunger Switch – J4 Series

A Plunger Switch Built to Last – J4 Series

Our high-performance plunger switches use the same patented “double seal” ball carrier design as the J4 ball switch. CPI offers tremendous flexibility in mounting and details of actuator parameters. These ultra-rugged plunger switches can be configured for the most demanding applications with a wide variety of contact options. Both custom and off the shelf, versions are available.


  • Stainless steel construction
  • Completely submersible (meets IP68)
  • Plunger seals, wiper seals and hardenend actuator configurations
  • Ultra high-temperature capability
  • Normally open and normally closed versions available

Variable parameters

  • plunger length
  • actuator shape/size
  • mounting thread
  • terminations
  • actuation force
  • travel parameters
  • sealed or vented extension
  • seal configuration
  • normally open and normally closed versions available


  • Hatch / door interlock switch (amphibious military vehicles)
  • valve position sensing (diesel turbochargers, coking ovens)
  • cab down position sensing
  • service door interlock (safety shut-down)
  • hydraulic valve handle position sensing

Electrical Ratings 28VDC, 5A

Endurance: (28VDC)
5A 100,000 cycles
Please contact the factory to discuss your electrical and endurance requirements.
Operating Temperature:
Non-heat sink models -40ºF to 257ºF
Heat sink / Special Designs -40°F to 302°F (up to 400°F plunger area only designs available)

Related Content

Hardened Ball & Plunger Switches Get the Job Done

Take the Plunge with a CPI Plunger Switch!

5 Reasons You Can’t Kill Our Plunger Switches

Plungers on Poles

CPI Switches Detect circuit break trips on utility towers

Make The “Switch” to CPI

If your switching application demands high performance, we think you should demand CPI. Please call us today to speak with our engineering team about your needs.

(973) 887-9400